We have used the DMC-3000s at St. Lucie since early 2014. We have seen a shift in the DMC-3000 correction factor from 1.10 to 1.03. The DMC-2000 correction factor was 1.15 prior to the change to the 3000s. The energy response of the DMC-3000 is different than the DMC-2000. You should look at the energy response curves and what correction factor you are using. This may be the reason for the shift, but I wouldn't expect it to be just certain individuals or work groups. During outages, based on the average energy photons in certain areas, we have seen some differences in response for certain work groups, but not significant. However, we did see a collective mismatch in estimated vs. TLD after the first TLD read. We made an immediate change in the next DMC-3000 calibration cycle. Our current bias is just over +1% for the DMC-3000.
Feel free to call me if you'd like more information! Brent Robinson RP Technical Superintendent St. Lucie Nuclear Plant 772-467-7308 From: Macho, Michael [mailto:[email protected]] Sent: Tuesday, July 12, 2016 5:25 PM To: [email protected]; [email protected] Subject: [powernet] DMC 3000 G2 electronic dosimeters increased response. CAUTION - EXTERNAL EMAIL We are completing the first six month monitoring period using DMC3000 G2 version electronic dosimeters and have noticed that individual departments (e.g., Security) and individuals who previously received little or no exposure and make numerous entries now are accumulating small amounts during the week. I would not expect to receive the processed TLD results for a month. My questions are: 1) I would like to know if any other DMC3000 users have experienced similar occurrences? 2) Has the increase in estimated dose resulted in an increase in TLD/OSL to estimated (DMC3000) dose mismatch? Michael Macho Radiation Protection Supervisor [email protected]<mailto:[email protected]> [cid:[email protected]] SAFETY is first QUALITY SCHEDULE Luminant Power Comanche Peak Nuclear Power Plant 6322 North FM 56 or PO Box 1002 Mail Code 005A Glen Rose, TX 76043 (254)897-5698
